Since the distribution was paid to you personally, a rollover of the entire gross amount would require that within 60 days of receipt of the distribution you deposit the money into another qualified retirement account like an IRA.
Yes, "Savers Credit" is a common nickname for the Retirement Savings Contribution Credit calculated on Form 8880. If you do not roll your recent distribution over, you'll have to file an amended tax return (Form 1040-X) along with an amended 2019 Form 8880 to account for this distribution reducing the amount of the credit originally calculated on this form (assuming that you did not already include this distribution on line 4 of this form), and pay the balance due. It may end up being that the entire credit is disallowed and you'll have a balance due of $150 with your amendment. (This is an anti-abuse provision to prevent you from taking money out of a retirement account just to put it back in just to get the credit without actually increasing your retirement savings. This applies even if you take the money out after filing but before the due date of your tax return, as you did in this case.)
Be aware that you are only allowed one rollover in a 365-day period (actually 366 days since this is a leap-year).
